Riverhead Town is in line to receive $8.09 million from Suffolk County to help ease the pain of funding state and federally mandated upgrades to its main sewer treatment plant near Indian Island County Park, which are expected to cost up to $22 million.

The plant, built in 1937, has already been upgraded twice, most recently in 2000, to meet previous state Department of Environmental Conservation requirements, said Supervisor Sean Walter.

The deadline for completing these additional required upgrades is January 2014 but the town is expected to apply for an extension.

Suffolk County Executive Steve Bellone announced at a press conference Monday that Riverhead Town — which must now upgrade both the level of treatment it provides and the capacity the plant can handle — had been unanimously recommended by the county’s sewer infrastructure committee to receive the award.

About $28 million in grants and loans were announced Monday, with Riverhead grabbing the lion’s share. The money comes from the county’s voter-approved 1/4 percent sales tax, which is used for environmental programs.

“These are projects that have gone though the process and have been approved, the engineering is done. They are ready to go,” Mr. Bellone said, describing Riverhead’s project and others slated to receive grant money as “shovel-ready.”

In addition to the grant, Riverhead’s sewer upgrade also qualified for $4 million in county loans.

Mr. Bellone also said that the privately developed 19-unit apartment project at downtown Riverhead’s former Woolworth building had qualified for $800,000 in grants.

The county had about $33 million left over in the sewer stabilization portion of its voter-approved quarter-cent sales tax program, which is used for drinking and surface water protection. County officials decided to use that money on sewer upgrade projects, Mr. Bellone said. Only about $8 million will remain in the fund, Mr. Bellone said.

“That’s why it was important for Riverhead to get in on this, because it’s not going to be available next year,” said Suffolk County Legislator Al Krupski (D-Cutchogue), whose district spans the North Fork.

The awards still need to be approved by the county Legislature, Mr. Bellone said, and a bill that would allocate the money is being introduced today, Thursday. The Legislature will then vote at its Oct. 8 meeting.

Riverhead is seeking to upgrade the capacity of its sewer plant on Riverside Drive from 1.2 million gallons per day to 1.4 million.

The town is also looking to upgrade its ability to remove nitrogen from the treated effluent that is discharged into the bay by about 75 percent, officials said.

Riverhead sewer district superintendent Michael Reichel said the Town has about $10 million available through the district’s remaining fund balance and state grants. The county’s $8 million grant would leave the town about $4 million short of the total it needs to upgrade the facility.

Mr. Reichel said the town has submitted to take out a $4 million low-interest loan through the state’s Environmental Facilities Corporation.

“We’ve made applications to them,” he said. “We’ve cleared their hurdles for financing.”

Mr. Walter — who did not attend Monday’s event due to a family emergency — later said he was “grateful” to the county executive for clearing the funding.

“You’re going to see us move very quickly now,” Mr. Walter said. “We hope to have the bid specifications issued by the next [Town Board] meeting or the first meeting in October and we hope to award a contract for this job early next year.”

Mr. Krupski noted that the town has all its permits in place to start the work.

“This is shovel-ready money,” he said. “It’s brick and mortar, it’s not for planning or ‘Someday I’d like to do something; I have a dream.’ This is real money that’s going to have a real impact today. And that’s important.”

The town also has approval to use the effluent from its sewage treatment plant as fertilizer for the county golf course next door, Mr. Krupski added.

“They just have to hook into the existing irrigation system,” he said.

Riverhead also will be looking for grant money to offset the cost of upgrading its Calverton sewer plant, which expected to cost another $20 million, Mr. Walter said.

For that project, the town has applied for grants from a different program, the state’s Regional Economic Development Council.